diff --git a/functions.php b/functions.php
index cd1cc4c..0eb2dd7 100644
--- a/functions.php
+++ b/functions.php
@@ -35,6 +35,13 @@ function validateEmail($email)
  */
 function sanitizeInput($input)
 {
+    // Handle non-string values
+    if (is_array($input)) {
+        return array_map('sanitizeInput', $input);
+    }
+    if (!is_string($input)) {
+        $input = (string)$input;
+    }
     return htmlspecialchars(trim($input), ENT_QUOTES, 'UTF-8');
 }
 
@@ -422,7 +429,16 @@ function redirect($url)
  */
 function post($key, $default = '')
 {
-    return isset($_POST[$key]) ? sanitizeInput($_POST[$key]) : $default;
+    if (!isset($_POST[$key])) {
+        return $default;
+    }
+    
+    // If the value is an array, return the first element or default
+    if (is_array($_POST[$key])) {
+        return !empty($_POST[$key]) ? sanitizeInput($_POST[$key][0]) : $default;
+    }
+    
+    return sanitizeInput($_POST[$key]);
 }
 
 /**